Lifting-magnet.



A. G. EASTWOOD.

LIFTING MAGNET.

APPLICATION FILED FEB. 15, 1906.

950,718, Patented Mar. 1,1910.

wrrmssszsz INVEN'I'OP ATTORNEYS ARTHUR C. EASTWOOD, OF CLEVELAND, OHIO.

LIF'IING-MAGNET.

Specification of Letters Patent.

Patented Mar. 1, 1910.

Application filed February 15, 1906. Serial No. 301,293.

To all whom it may concern:

Be it known that I, ARTHUR C. EASTWOOD, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented'or discovered new and useful Improvements in Lifting- Magnets, of which. the following is a specification.

The object of my invention is to increase the durability of lifting magnets through the better protection of the magnetizing coil, to decrease the cost of repairs, and to facilitate the making of repairs.

My invention applies particularly to that type of lifting magnet described in U. S. Patent No. 794,086 issued to me, July t, 1905, though it is applicable, with beneficial results, to other forms of lifting magnets.

The magnet described in United States Patent, N o. 794,086,-is a very powerful one and when it is used for handling pig iron for instance, the pigs of iron will jump through a vertical distance of several inches to attach themselves to the lower face of the magnet. This results in a series of blows of considerable-force as each pig of iron may weigh l00'p0unds. This of course produces wear of the brass plate which protects the lower side of the coil and eventually the plate may be worn to such an extent as to allow it to spring inward thus damaging the coil. The brass plate is customarily held in place by screws passing through it into the inner and outer pole pieces/of the'magnet. These ,screws also become'battered by the repeated blows delivered by the material attracted by the magnet so that their removal becomes very diflicult. The repair of the magnet including the renewal of the coil and the brass plate is thcref'orea tedious and expensive matter. My present invention provides means for overcoming these difficulties and embraces also means for deadening the vibration which otherwise might be transmitted to the coil with injurious results, together with means for compensating for the expansion of the winding without injuryto the insulation and certain other details of construction which will be hereinafter described.

The drawing shows in Figure l, a vertical cross section of a magnet embodying my improvements, and in Fig. 2, a plan of the right ortion of Fig. 1.

In t e drawing A is the frame of the magnet, made of magnetic material, preferably annealed steel. The frame A is provided on its upper surface with radial ribs a rand around its periphery, with vertical ribs a These ribs are provided for increasing the.

surface available for dissipating the heat generated in the magnetizing coil. They are also so disposed as to mechanically stiffen and strengthen the frame. of the magnet; at the same time, they are so arranged, with reference to the direction of magnetic flux, that their full section is available for conducting the magnetic flux. By this construction, increased radiating surface, increased strength, and maximum section of magnetic circuit'are obtained with minimum weight of material.

The frame A is provided with a downwardly projecting core N, the lower face of which forms one pole of the magnet. The outer annular projection of the frame'A forms a second pole-piece. I

' B is the magnetizing'coil which surrounds the core N and approximately fills the space between the core N and the annular pole S. It is to be noted that the annular face of the pole S is considerably lower than the face of the pole N and that the magnetizing coil B is thicker at'its outer than atits inner diameter. This construction is used for the reasons given in United States Patent No. 794,086, issued to me, July 4, 1905. The lower face of the coil B is held in place and protected by a non-magnetic plate C (made, for instance, of brass), which plate engages at its inner and outer edges with finished shoulders in the poles N and S. The plate C is held in place andis shielded by an annular non-magnetic plate C-, which is held in position at its inner edge or centralopening by the tapered pole'shoe n, which 111 turn is held bya bolt at extending through the core N. This bolt is threaded and provided with a nut at its upper end screwed down on the core N. The plate C is clamped at its periphery by a series of bolts 8 which pass through lugs s on the outer surface of the pole piece S and have their heads in the lower face of the piece. The lugss are located between the ribs a in such a. manner that the nuts which hold the bolts .9 in place are protected and are not liable to become bruised and battered in service. A sheet of elastic material 0 such as rubber packing, is placed between the plates C and C and has the elfect of deadeningany blows which may delivered on adds to the cross-section of the circuit of the magnetic flux.

the ribs being substantially coincident with tween said ribs.

5.. A magnet, having its upper and lateral portions provided with ribs, the. length of the ribs being coincident with the directions of the magnetic flux in the'magnetic circuit.

6. A magnet having its u per and lateral portions provided with ribs so arranged that the'cross-section of each, of ,said'ribs 7. A magnet having the top portions of its frame provided withribs, the length of the directions of the magnetic flux in said portions of the frame. 1

8. In a. lif -'ng magnet, a frame provided with ribs, a magnetizing coil in the frame, a wear plate on the bottom of said frame, bolts to secure the frame and plate together, and securing means for said bolts seated be- 9, In a magnet, a chamber, a magnetizing coil therein, and-plastic material surrounding the 0011, said chamber havmg an aperture, through which the leads from said coil pass and a portion of said plastic material may be displaced to compensate for the expansion of the coil. i

10. In a magnet, a chamber, a magnetizi ing coil therein, and plastic material surroundingthe coil, said chamber having a cavity into which a portion of said plastic material may be forced when the coil expands.

11. In a magnet, a chamber, a magnetizing Winding therein, and a material to seal the Winding in the chamber, said material becoming plastic when heated, there being a passage in a wall of the chamber, into which a portion of the plastic material may be displaced by the expansion of saidwindmg.

12. In a magnet, a frame, a magnetizing coil therein, said frame being provided with.

holes extending therethrough into the space occupied by the coil, and followers between the coil and the frame and in line with said holes and means insertible in said holes and engageable with said followers to force the coil from the frame.

ARTHUR C. EASTW'OOD.

Witnesses:

C. W. Corrsroon, J. H. I'IALL. 

